| Fiscal period | 2025 | 2024 | 2023 | 2022 | 2021 | 2020 | 2019 | 2018 | 2017 | 2016 |
| Period End Date | 12/31/2025 | 12/31/2024 | 12/31/2023 | 12/31/2022 | 12/31/2021 | 12/31/2020 | 12/31/2019 | 12/31/2018 | 12/31/2017 | 12/31/2016 |
| Sales | 17,942.00 | 17,168.00 | 16,478.00 | 15,228.00 | 13,022.00 | 11,797.00 | 11,486.00 | 11,221.00 | 10,424.86 | 10,137.20 |
| Total Revenues | 17,942.00 | 17,168.00 | 16,478.00 | 15,228.00 | 13,022.00 | 11,797.00 | 11,486.00 | 11,221.00 | 10,424.86 | 10,137.20 |
| Cost of Merchandise Sold | 10,933.00 | 10,410.00 | 9,982.00 | 9,379.00 | 8,302.00 | 7,559.00 | 7,089.00 | 6,873.00 | 6,327.30 | 6,022.65 |
| Gross Profit | 7,009.00 | 6,758.00 | 6,496.00 | 5,849.00 | 4,720.00 | 4,238.00 | 4,397.00 | 4,348.00 | 4,097.56 | 4,114.56 |
| Warehousing, marketing and administrative expenses | 4,514.00 | 4,121.00 | 3,931.00 | 3,634.00 | 3,173.00 | 3,219.00 | 3,135.00 | 3,190.00 | 3,048.90 | 2,995.06 |
| Restructuring charges | -- | -- | -- | -- | -- | -- | -- | -- | -- | -- |
| Operating Earnings (Loss) | 2,495.00 | 2,637.00 | 2,565.00 | 2,215.00 | 1,547.00 | 1,019.00 | 1,262.00 | 1,158.00 | 1,048.66 | 1,119.50 |
| Interest expense | 81.00 | 77.00 | 93.00 | 93.00 | 87.00 | 93.00 | 79.00 | 88.00 | 80.46 | 66.33 |
| Write-offofinvestmentsinunconsolidatedentities | -- | -- | -- | -- | -- | -- | -- | -- | -- | -- |
| Gain on sale of unconsolidated entity | -- | -- | -- | -- | -- | -- | -- | -- | -- | -- |
| Equity in income of unconsolidated entities - net | -- | -- | -- | -- | -- | -- | -- | (19.00) | (37.77) | -- |
| Loss on liquidation of investment in unconsolidated entity | -- | -- | -- | -- | -- | -- | -- | -- | -- | (31.19) |
| Interest income | -- | -- | -- | -- | -- | -- | -- | 6.00 | 2.57 | 0.72 |
| Unclassified-net | -- | -- | -- | -- | -- | -- | -- | -- | -- | -- |
| Other non-operating income | 16.00 | -- | -- | -- | -- | -- | -- | -- | -- | 1.30 |
| Other non-operating expense | -- | 24.00 | 28.00 | 24.00 | 25.00 | 21.00 | 26.00 | 24.00 | 2.32 | (4.93) |
| Total other expense (Non-operating) | 65.00 | 53.00 | 65.00 | 69.00 | 62.00 | 72.00 | 53.00 | (77.00) | -- | (100.44) |
| Earnings before income taxes | 2,430.00 | 2,584.00 | 2,500.00 | 2,146.00 | 1,485.00 | 947.00 | 1,209.00 | 1,081.00 | 935.32 | 1,019.06 |
| Income taxes | 622.00 | 595.00 | 597.00 | 533.00 | 371.00 | 192.00 | 314.00 | 258.00 | 312.88 | 386.22 |
| Currentprovision:Federal | -- | -- | -- | -- | -- | -- | -- | -- | -- | -- |
| Currentprovision:State | -- | -- | -- | -- | -- | -- | -- | -- | -- | -- |
| Currentprovision:Foreign | -- | -- | -- | -- | -- | -- | -- | -- | -- | -- |
| Deferredtaxprovision(benefit):Federal | -- | -- | -- | -- | -- | -- | -- | -- | -- | -- |
| Deferredtaxprovision(benefit):State | -- | -- | -- | -- | -- | -- | -- | -- | -- | -- |
| Deferredtaxprovision(benefit):Foreign | -- | -- | -- | -- | -- | -- | -- | -- | -- | -- |
| Deferred tax benefits | -- | -- | -- | -- | -- | -- | -- | -- | -- | -- |
| Earnings before cumulative effect of accounting change | -- | -- | -- | -- | -- | -- | -- | -- | -- | -- |
| Cumulative effect of accounting change | -- | -- | -- | -- | -- | -- | -- | -- | -- | -- |
| Net Earnings | 1,808.00 | 1,989.00 | 1,903.00 | 1,613.00 | 1,114.00 | 755.00 | 895.00 | 823.00 | 622.44 | 632.84 |
| Less: Net earnings attributable to noncontrolling interest | 102.00 | 80.00 | 74.00 | 66.00 | 71.00 | 60.00 | 46.00 | 41.00 | 36.71 | 26.91 |
| Distributed earnings available to participating securities | -- | -- | -- | -- | -- | -- | -- | 2.00 | -- | 2.38 |
| Undistributed earnings available to participating securities | -- | -- | -- | -- | -- | -- | -- | 4.00 | -- | 3.04 |
| Net earnings attributable to W.W. Grainger, Inc | 1,706.00 | 1,909.00 | 1,829.00 | 1,547.00 | 1,043.00 | 695.00 | 849.00 | 776.00 | 585.73 | 600.50 |
| Numerator for diluted earnings per share | -- | -- | -- | -- | -- | -- | -- | -- | -- | -- |
| Earnings per share before cumulative effect of accounting change: Basic | -- | -- | -- | -- | -- | -- | -- | -- | -- | -- |
| Cumulative effect of accounting change: Basic | -- | -- | -- | -- | -- | -- | -- | -- | -- | -- |
| Net Earnings Per Share (Basic) | 35.47 | 38.84 | 36.39 | 30.22 | 19.94 | 12.88 | 15.39 | 13.82 | 10.07 | 9.94 |
| Earnings per share before cumulative effect of accounting change: Diluted | -- | -- | -- | -- | -- | -- | -- | -- | -- | -- |
| Cumulative effect of accounting change: Diluted | -- | -- | -- | -- | -- | -- | -- | -- | -- | -- |
| Net Earnings Per Share (Diluted) | 35.40 | 38.71 | 36.23 | 30.06 | 19.84 | 12.82 | 15.32 | 13.73 | 10.02 | 9.87 |
| Weighted Average Shares Outstanding (Basic) | 47.90 | 48.90 | 49.90 | 50.90 | 51.90 | 53.50 | 54.70 | 56.10 | 57.67 | 60.43 |
| Weighted Average Shares Outstanding (Diluted) | 48.00 | 49.00 | 50.10 | 51.10 | 52.20 | 53.70 | 54.90 | 56.50 | 57.98 | 60.84 |